We propose a 2-arm, parallel group, randomized controlled trial to test the efficacy of an after school ethnic dance program plus a culturally-tailored, home-based screen time reduction intervention (delivered by bilingual, Latina, Community Health Advisors) to reduce weight gain (body mass index) among lower socioeconomic status, pre-adolescent Latina girls. The control group will receive an "active-placebo" information-based health education intervention. A total of 240 7-9 year old girls will be randomized to the two conditions, and both interventions will last for the full 2-year period of the study for each girl. Latina girls are at increased risk of obesity and obesity-related morbidities. However, effective and generalizable obesity prevention programs for this rapidly growing population are not available. Our proposed interventions are supported by our past and ongoing studies, demonstrating their feasibility, desirability and potential efficacy to reduce weight gain in preadolescent children. All interventions will be further developed, revised, and pilot-tested with Latina girls and their families through formative research. Girls will be recruited from six public elementary schools serving low-income Latino communities in San Jose, CA. Measures will be collected in girls' homes at baseline, 6, 12, 18 and 24 months. Body Mass Index (BMI) is the primary outcome measure. The primary outcome analysis will compare individual trajectories of change in BMI in the treatment and control groups over the entire two-year course of the trial, using random regression models. The study is powered (90%) to detect a clinically-significant effect. Primary hypothesis: Compared to controls, girls in the treatment group will significantly reduce their weight gain (BMI) over the two-year study period. Secondary hypotheses: Compared to controls, girls in the treatment group will significantly reduce their waist circumference, triceps skinfold thickness, systolic and diastolic blood pressures, resting heart rate, television, videotape/DVD and video game use, meals eaten with TV, daily dietary energy intake, percent of energy from fat, and weight concerns, and significantly increase their daily physical activity, daily moderate to vigorous physical activity, liking for physical activity, self-esteem, and school performance. In addition, we will evaluate potential demographic, cultural, psychological, and biological moderators and mediators of intervention effects on BMI and secondary outcomes, evaluate correlates and risk factors for change in BMI and secondary outcomes, and evaluate intervention delivery/process variables. Relevance to public health: We are experiencing an epidemic of obesity. Latina girls are at higher risk of obesity and associated medical problems. However, effective prevention programs are lacking. We propose to develop and test a promising and potentially generalizable public health program for Latina girls.